Automated quoting of molds and molded parts

ABSTRACT

Automated, custom mold manufacture for a part begins by creating and storing a collection of information of standard tool geometries and surface profiles machinable by each of the standard tool geometries. A customer sends a CAD file for the part to be molded to the system. The system assesses the CAD file to determine various pieces of mold manufacturing information. One or more acceptability criteria are applied to the part, such as whether the part can be manufactured in a two-piece, straight-pull mold, and whether the mold can by CNC machined out of aluminum. If not, the system sends a file to the customer graphically indicating which portions of the part need modification to be manufacturable. The system provides the customer with a quotation form, that allows the customer to select several parameters, such as number of cavities, surface finish and material, which an independent of the shape of the part. The quotation module then provides the customer with the cost to manufacture the mold or a number of parts. The quotation is based in part upon mold manufacturing time as automatically assessed from the part drawings and based in part on the independent parameters selected by the customer. The customer&#39;s part is geometrically assessed so the system automatically selects appropriate tools and computes tool paths for mold manufacture. In addition to the part cavity, the system preferably assesses the parting line, the shutoff surfaces, the ejection pins and the runners and gates for the mold. The preferred system then generates CNC machining instructions to manufacture the mold, and the mold is manufactured in accordance with these instructions.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/056,755 of Lawrence J. Lukis et al., filed Jan. 24, 2002 nowU.S. Pat. No. 6,701,200, entitled AUTOMATED CUSTOM MOLD MANUFACTURE,incorporated by reference herein, which claims priority from provisionalpatent application No. 60/344,187, filed Dec. 27, 2001, entitledAUTOMATED MANUFACTURE OF STRAIGHT PULL MOLDS FOR CUSTOM PLASTIC PARTS.This application also claims priority from provisional patentapplication No. 60/386,658 of Lawrence J. Lukis et al., filed Jun. 5,2002, entitled IMPROVED PROTOTYPE QUOTING.

BACKGROUND OF THE INVENTION

The present invention relates to the field of mold making, andparticularly to the manufacture of molds, such as for use with injectionmolding presses, from blocks of metal. More specifically, the presentinvention relates to software supported methods, systems and tools usedin the design and fabrication of molds for custom plastic parts, and inpresenting information to customers for the customer to have selectiveinput into various aspects of such design and fabrication which affectprice of a customized part profile.

Injection molding, among other types of molding techniques, is commonlyutilized to produce plastic parts from molds. Companies and individualsengaged in fabricating molds are commonly referred to as “moldmakers.”In many cases (referred to as “straight pull” injection molding), themold consists of two metal blocks, one top and one bottom. Mostcommonly, the metal blocks are high quality machine steel, so the moldwill have an acceptably long life. Opposed surfaces of each mold blockare machined to jointly produce the required cavity in the shape of thedesired part, as well as “shut-off” surfaces sealing the cavity when themold blocks are pressed together. The line on which shut-off surfacesintersect with the surface of the cavity is called the parting line. Thecorresponding line on the surface of the part formed by the parting lineis called the witness mark. After the mold assembly is set up in aninjection molding press, parts are made by filling the cavity withmolten plastic. The mold blocks are separated from each other aftersolidification of the molten plastic. The plastic part, normallysticking after separation to the bottom block, is then ejected by meansof ejectors.

The moldmaking art has a long history of fairly gradual innovation andadvancement. Molds are designed pursuant to a specification of the partgeometry provided by a customer; in many cases, functional aspects ofthe plastic part also need to be taken into account. Historically,moldmaking involves at least one face-to-face meeting between themoldmaker and the customer, in which the customer submits detailed partgeometry, usually with the aid of drawings, to the moldmaker andoutlines the function of the part. Armed with knowledge of injectionmolding technology, the moldmaker designs the mold corresponding to thedrawings of the part. In particular, the moldmaker orients the part toenable a straight pull mold separation, splits its surface into twoareas separated by a suitable parting line, and replicates these areasin the top and bottom blocks. The moldmaker determines the location andshape of the shut-off surfaces and enlarges the dimensions of the cavityrelative to the desired part as necessary to account for shrinkage ofthe plastic material. The moldmaker determines the size and position ofone or more gates and runners to provide an adequate flow path for themolten plastic shot into the cavity. Sizes and locations of openings forejection pins are also selected by the moldmaker. The machiningoperations to be performed to fabricate the designed mold are determinedby the moldmaker. The moldmaker then runs various cutting tools, such asendmills, drills and reams, to machine the basic cavity, shut-offsurfaces, runners, gates and ejector pin openings in blocks of metal. Toproduce certain hard-to-mill features in the mold, the moldmaker mayalso design and machine electrodes, and then perform electro-dischargemachining (“EDM”) of the mold blocks. The moldmaker then outfits themold blocks with ejection pins and prepares the mold assembly for use inthe injection molding press. Throughout all of this design andfabrication, the moldmaker makes numerous design choices pertaining tothe geometric details of the cavities to be machined as well as to thetools to be used for machining.

All these steps involve a high degree of skill and experience on thepart of the moldmaker. Experienced moldmakers, after having consideredthe design submitted by the customer, may sometimes suggest changes tothe part geometry so that the part is more manufacturable and lesscostly. Highly experienced, gifted moldmakers can charge a premium fortheir services, both in return for the acuity of their experience andperception in knowing what will and will not work in the mold, and inreturn for their skill, speed and craftsmanship in machining the mold.

Because of the large number of technical decisions involved andconsiderable time spent by highly skilled moldmakers in analyzing indetail the part geometry by visual inspection, obtaining a desiredinjection mold has generally been quite expensive and involved asignificant time delay. A single mold may cost tens or hundreds ofthousands of dollars, and delivery times of eight to twelve weeks ormore are common.

As in many other areas of industry, various computer advances have beenapplied to the moldmaking art. Today, most of customer's drawings arenot prepared by hand, but rather through commercially available programsreferred to as CAD (Computer-Aided Design) software. To produce drawingsof the molds based on the drawings of custom parts, moldmakers also useCAD software, including packages developed specifically for this task.Also, in most moldmaking companies machining operations are not manuallycontrolled. Instead, CNC (Computer Numerical Control) machines such asvertical mills are used to manufacture molds and, if needed, EDMelectrodes in accordance with a set of CNC instructions. To computedetailed toolpaths for the tools assigned by the moldmaker and toproduce long sequences of such instructions for CNC mills, computersrunning CAM (Computer-Aided Manufacturing) software (again, includingpackages developed specifically for the moldmaking industry) are used bymost moldmakers. CAD/CAM software packages are built around geometrykernels—computationally intensive software implementing numericalalgorithms to solve a broad set of mathematical problems associated withanalysis of geometrical and topological properties of three-dimensional(3D) objects, such as faces and edges of 3D bodies, as well as withgeneration of new, derivative 3D objects. At present, a number of matureand powerful geometry kernels are commercially available.

While existing CAD/CAM software packages allow designers and CNCmachinists to work with geometrically complex parts, they are still farfrom completely automating the designer's work. Rather, these packagesprovide an assortment of software-supported operations that automatemany partial tasks but still require that numerous decisions be made bythe user to create the design and generate machining instructions.CAD/CAM packages usually facilitate such decisions by means ofinteractive visualization of the design geometry and machining tools.This makes software applicable to a wide variety of tasks involvingmechanical design and machining operations. The downside of suchversatility, when applied to moldmaking, is that it results in long andlabor intensive working sessions to produce mold designs and CNCmachining instructions for many custom parts, including parts lendingthemselves to straight pull molding.

Visualization allows the moldmaker to evaluate whether the mold andinjection molded parts can be made sufficiently close to the designusing available tools. The fidelity with which plastic parts can bemanufactured is limited by the finite precision of mills and cuttingtools used to machine the mold, and by shrinkage of plastic materials(slightly changing the shape and dimensions of the injection moldedparts as they cool down and undergo stress relaxation in a way that islargely but not entirely predictable). These rather generic factorsestablish the level of dimensional tolerances for injection-moldedparts, the level that is generally known and in most cases acceptable tothe customers.

Oftentimes, however, additional factors come into play that can resultin more significant deviations of injection molded plastic parts fromthe submitted design geometry. These factors are usually associated withcertain features that are hard to machine in the mold using verticalmills. For example, very thin ribs in the part can be made by cuttingdeep and narrow grooves in the mold, but may require an endmill with animpractically large length to diameter ratio. Machining of anglesbetween adjacent faces joined by small radius fillets (and, especially,of angles left without a fillet) may result in similar difficulties.Exact rendering of such features may substantially increase the cost ofthe mold, and even make its fabrication impractical with the technologyavailable to the moldmaker.

Obviously, such manufacturability issues need to be identified,communicated to the customer, and, if necessary, rectified beforeproceeding with mold fabrication. Their resolution normally requirestight interaction between the moldmaker and the customer, as bothparties are in possession of complementary pieces of information neededto resolve the issues. The moldmaker has first hand knowledge of themold fabrication technology available to him, while the customer,usually represented in this process by the part designer, has first handunderstanding of part functionality and cosmetic requirements. Based onthis understanding, the customer can either agree to the anticipateddeviations of part geometry from the submitted specification, or, if thedeviations are unacceptable, the customer can modify the part design toresolve manufacturability issues without compromising functional andcosmetic aspects of the design.

As plastic parts often have many unnamed (and hard to name) features,pure verbal communication not supported by visualization of the part canbe awkward and misleading. Therefore, communicating such informationrequires a face-to-face meeting with the customer, in which themoldmaker and the customer view the drawing or image of the part anddiscuss the issues in detail. Such meetings take a considerable amountof time, both from moldmakers and their customers, and increase businesscosts.

Resolution of manufacturability issues is closely connected with pricequotations requested by customers. When a customer requests a pricequotation for a molding project, the moldmaker informally applies awealth of experience and knowledge to predict costs and variousdifficulties in fabricating the mold. The potential moldmanufacturability issues should be substantially resolved before abinding quotation can be given to a customer. For this reason, it canoften take one or two weeks for a customer just to obtain a pricequotation. Quoting is performed at a stage when securing the order forthe moldmaking job is uncertain, and the cost of quoting must berecovered by the moldmaker from the subset of quotes that are actuallyaccepted.

In the event that the customer contracts with the moldmaker for the job,the quotation becomes a constituent part of the contract formanufacturing the mold and injection molded parts. For obvious reasonsthe informal quoting method is prone to human errors. If the request forquotation results in the job order, such errors will most likely becomeapparent during mold design and machining, or even after the mold isfinished and used for manufacturing the first plastic parts. The priceof such mistakes in terms of the lost time and effort, as well as interms of strained customer relations, may be rather high. Thus, for amoldmaking business to be successful and profitable, good communicationbetween the customer and the moldmaker in resolving manufacturabilityissues and accurate quoting are extremely important.

BRIEF SUMMARY OF THE INVENTION

The present invention is a method and system of automated, customquotation for manufacture of a mold and/or manufacture of a molded part.To begin the process, a customer sends a CAD file defining the surfaceprofile for the part to be molded to the system. The system thenassesses two different types of information to arrive at a quotation.First, the part surface profile (which could have any of a virtuallyinfinite number of shapes) is assessed, to consider certaincost-affecting parameters determined by the part surface profile.Further, the customer is provided with at least one menu ofcustomer-selectable values for a cost-affecting parameter unassociatedwith part surface profile. A quotation is then automatically generatedwhich varies based upon both (i.e., infinitely-customized andmenu-selected) types of information, and automatically transmitted tothe customer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary “cam” part desired by acustomer.

FIG. 2 is a flow diagram of the preferred method followed by the presentinvention to manufacture the mold for the exemplary “cam” part.

FIG. 3 is a representational view conceptually showing failure ofstraight pull in a y-axis direction.

FIG. 4 is a representational view conceptually showing acceptance ofstraight pull in a z-axis direction.

FIG. 5 is an elevational view of a standard endmill.

FIG. 6 is an exemplary product deviation file of the exemplary part ofFIG. 1.

FIG. 7 is a computer screen shot of a perspective view showing theselected tool paths of the standard endmill of FIG. 4 in fabricating themold for the exemplary part of FIG. 1.

FIG. 8 is a perspective view showing the parting line, the shut-offsurfaces, and the ejection pin locations for the exemplary part of FIG.1.

FIG. 9 is a perspective view showing sprews, runners, gates and ejectionpins for the mold for the exemplary part of FIG. 1.

FIG. 10 is a computer screen shot of a preferred customer interface forthe quotation system, showing customer selection of one parameter.

While the above-identified drawing figures set forth one or morepreferred embodiments, other embodiments of the present invention arealso contemplated, some of which are noted in the discussion. In allcases, this disclosure presents the illustrated embodiments of thepresent invention by way of representation and not limitation. Numerousother minor modifications and embodiments can be devised by thoseskilled in the art which fall within the scope and spirit of theprinciples of this invention.

DETAILED DESCRIPTION

The present invention will be described with reference to an exemplarypart 10 shown in FIG. 1. FIG. 1 represents a “cam” part 10 designed bythe customer. In part because the cam 10 is custom-designed (i.e., not astaple article of commerce) by or for this particular customer, the cam10 includes numerous features, none of which have commonly acceptednames. For purposes of discussion, we will give names to several ofthese features, including a part outline flange 12, a circular opening14 with two rotation pins 16, a non-circular opening 18, a notch 20, arib 22, a 60° corner hole 24, a 30° corner hole 26, and a partial web28. However, workers skilled in the art will appreciate that thecustomer may in fact have no name or may have a very different name forany of these features.

FIG. 2 is a flow chart showing how the present invention is used tomanufacture the customer's part. The first step involves a Customer DataInput module 30. Thus, the starting input for the present invention isthe CAD part design file 32, provided by the customer from thecustomer's computer 34. There are several standard exchange formatscurrently used in the 3D CAD industry. Presently the most widely usedformat is the Initial Graphics Exchange Specification (IGES) standard.The present invention accepts IGES, STL or various other formats, and iscompatible with all the commercial CAD products currently in use.

In contrast to most moldmaker's operations which involve an initialface-to-face meeting with the customer to discuss drawings, the presentinvention allows the customer to provide the CAD file 32 without aface-to-face meeting. Such communication could occur through a mailedcomputer disk or through a dial-up modem site. In particular, however,an address on a global communications network such as the internet 36 isconfigured to receive customer CAD files 32. While the address could bea simple e-mail address, the preferred address is a website on theworld-wide-web, configured to receive a CAD file 32 from a customer forthe part to be molded. The “web-centric” customer interface preferablyinclude a part submission page as part of the Customer Data Input module30, which allows the customer to identify which standard CAD/CAM formatis being used for the part drawings. Alternatively, the customer's CADfile 32 may be evaluated with an initial program which determines whichtype of standard CAD/CAM format is being used by the customer. If theCAD file 32 transmitted by the customer does not conform to a recognizedstandard CAD file format so as to be readable by the software of thepresent invention, the customer data input module returns an errormessage to the customer.

The customer's CAD file 32 entirely defines the part 10. The next stepin the process is performed by a geometry analyzer module 38, whichassesses the geometry of the customer's part 10 using a set ofacceptability criteria 40, 42, 44, 46. This geometry analyzer module 38is used to determine whether the mold for the part defined by thecustomer's CAD file 32 can be inexpensively manufactured in accordancewith the present invention. Various acceptability criteria can be used,depending upon the software and manufacturing capabilities used inautomated manufacturing of the mold.

For example, if the software and manufacturing capabilities are limitedto manufacturing straight pull molds only, the first preferredacceptability criterion 40 is whether the part can be molded in astraight pull mold. If desired, an individual may view the customer'sCAD file 32, either through a printout drawing or on-screen, to visuallyinspect and determine whether the part can be manufactured in a straightpull mold.

However, in the preferred embodiment, the program automaticallyidentifies whether the part can be manufactured in a straight pull mold.Automatic “straight pull” manufacturability identification 40 involvesselecting an orientation of the part in the customer's CAD file 32.Customers typically draw parts oriented with an x-, y- or z-axis whichcoincides with the most likely straight pull direction. FIGS. 3 and 4represent an example of this. First, the cam 10 is solid modelled in they-direction as a plurality of parallel line segments extending in they-direction as shown in FIG. 3. The geometry analyzer module 38 thenconsiders each line in the solid modeling, to determine whether the lineis continuous and intersects the part surface profile only at a singlebeginning and a single ending. As shown here, line 48 is a first linewhich fails this test, as it intersects the cam 10 three times: oncethrough the part outline flange 12 and twice on the sides of the 60°corner hole 24. The y-direction orientation of this part 10 thus failsto permit straight pull mold manufacturability 40. The cam 10 is nextsolid modelled in the z-direction as a plurality of parallel linesegments extending in the z-direction as shown in FIG. 4. The geometryanalyzer module 38 again considers each line in the solid modeling, todetermine whether the line is continuous and intersects the part surfaceprofile only at a single beginning and a single ending. As shown here inFIG. 4, all the line segments meet this test 40. Because the cam 10passed the test 40 in the z-direction, it is thus determined that thepart 10 can be oriented such that the z-direction is the straight pulldirection. Thus, the cam 10 can be formed with a straight pull mold withthe straight pull direction coinciding with the z-direction as drawn.

If desired, the “straight pull” manufacturability identification 40 canbe terminated once it is determined that at least one orientation of thepart 10 exists which can be manufactured with a straight pull mold.Preferably, additional tests continue to be automatically run by thegeometry analyzer module 38 to confirm the best orientation of the part10 which can be manufactured with a straight pull mold. For instance, asimilar x-direction test is run, which this cam part 10 fails similar tothe z-direction test. Similarly, additional orientational tests can berun, with the parallel lines in the solid modeling run at angles to thex-, y- and z-directions selected in the customer's CAD file 32. If thepart passes “straight pull” manufacturability 40 on two or moreorientations, then an assessment is made of which orientation should beused for the mold. Computer programmers will recognize that, once theacceptability criteria are defined to include a determination 40 ofwhether the part can be molded in a straight pull mold and theorientation necessary for molding in a straight pull mold, there aremany equivalent programming methods to apply this acceptabilitycriterion 40 to the customer's CAD file 32.

If the CAD file 32 for the part 10 fails the straight pullmanufacturability test 40 such as due to the presence of undercuts, thepreferred system provides the customer with a graphical image of thepart 10 in an orientation that comes closest to passing the straightpull manufacturability test 40, but further with faces that haveundercut portions highlighted. A comment is provided to the customerthat the design of the part 10 should be revised to get rid of theundercuts.

If desired, the “straight pull” manufacturability criterion 40 mayassess not only whether a straight pull mold is possible at the selectedorientation, but may further evaluate draft angle. Draft angle affectsthe ease of machining the mold, as vertical edges are more difficult tomachine. Draft angle also affects the ease of using the mold, as morevertical sides have a higher sticking force making ejection of the part10 from the mold more difficult. Thus, more robust ejection pin systemsmaybe needed for parts with high draft angles. For example, in apreferred straight pull manufacturability criterion 40, draft angles onall sides of at least 0.5° are required. The straight pullmanufacturability criterion 40 will thus automatically identifyzero-drafted (vertical) surfaces and reject such parts as failing thestraight pull manufacturability criterion 40.

In the preferred embodiment, the present invention further reviews thepart design using a second acceptability criterion 42, of whether themold geometry can be formed through machining with a standard set of CNCmachining tools. This second acceptability criterion 42 involvesdetermining which tools are available, what are limitations in using theavailable tools, and defining areas of the mold (if any) which cannot bemachined with the available tools. Because this second acceptabilitycriterion 42 has significant overlap with generating the automated setof CNC machining instructions in the tool selection and tool pathcomputation module 68, it is discussed in further detail below. Inparticular, however, the preferred standard CNC machining tools includea collection of standard-sized endmills, standard-sized reams andstandard-sized drills. With this collection of standard CNC machiningtools, limitations exist with respect to the radii of curvature ofvarious edges and corners, and with respect to aspect ratio of deepgrooves in the mold. In general, an edge of a part cannot have a tighterradius of curvature than the smallest endmills and drill bits. Ingeneral, any grooves in the mold, which correspond to any ribs in thepart, must have an aspect ratio which permits at least one of thestandard CNC machining tools to reach the depth of the groove.

For example, FIG. 5 depicts the profile of a standard ¼ inch diameterball endmill 50. This endmill 50 has a cutting depth 52 of slightly lessthan 2 inches limited by a collet 54. If a ¼ inch thick groove in themold has a height of 2 inches or more, then the standard ¼ inch diameterendmill 50 cannot be used to form the groove portion of the cavity. Theaspect ratios of standard endmills are based upon the strength of thetool steel (so the tool 50 won't easily break in use), and follow asimilar aspect ratio curve. That is, all endmills which are less than ¼inch in diameter are shorter than the standard ¼ inch diameter ballendmill 50. All endmills which are longer than 2 inches are wider than ¼inch in diameter. Thus, no tool in the standard set can be used to makea groove ¼ inch thick with a height of 2 inches or more. As anapproximate rule, ribs should be no deeper than ten times their minimumthickness. The geometry analyzer module 38 includes analysis 42 runagainst the customer's CAD file 32, to conceptually compare the partshape against collected geometric information of a plurality of standardtool geometries, such a standard endmills. For the cam 10, all of theCAD file 32 passes except for the rib 22, which is too thin and long.

The preferred CNC machining criterion 42 further considers aspect ratiosof grooves relative to the parting line of the mold. Because endmillscan be used downward in the bottom half (cavity) of the mold and upwardin the top half (core) of the mold, aspect ratios of features whichcontain the parting line can be twice that of aspect ratios of featureswhich do not contain the parting line. That is, groove depth is measuredrelative to the lowest adjacent extending surface on the half of themold in which the groove is machined. In the cam 10, for instance, theinside edge of the part outline flange 12 does not intersect the partingline, because the parting line extends along the inside edge of thepartial web 28. The depth of the part outline flange 12 is thereforemeasured relative to the adjacent extending surface, the partial web 28.The aspect ratio determined by this depth of the part outline flange 12relative to the thickness of the part outline flange 12 must be withinthe aspect ratio of at least one tool in the standard set. In contrast,the outer edge of the part outline flange 12 has no adjacent extendingsurface and intersects the parting line. Because the parting lineseparates the outer edge of the part outline flange 12 into the two moldblocks, the depth of the outer edge of the part outline flange 12relative to its thickness can be up to twice the aspect ratio of atleast one tool in the standard set.

The CNC machining criterion 42 runs similar programming analysis toverify that each corner of the part 10 has a sufficient radius ofcurvature to permit machining by one of the standard CNC machiningtools. For instance, the CNC machining criterion may limit the minimumradius of outside corners of the part to no less than ½ the minimum wallthickness. If the CAD file 32 fails either due to having too deep ofgrooves or having too tight of corners, the part fails the CNC machiningcriterion 42, and the customer must be informed. Computer programmerswill recognize that, once the acceptability criteria 42 are defined toinclude a determination of whether groove depths and/or corner radii ofthe part permit standard CNC machining, there are many equivalentprogramming methods to apply this acceptability criterion to thecustomer's CAD file 32.

In the preferred embodiment, the geometry analyzer module 38 furtherreviews a third acceptability criterion 44, of whether the mold geometrycan be formed in aluminum or in an aluminum-based alloy. That is, adesign parameter imposed upon the preferred system is that the mold bemanufacturable from standard aluminum-based mold block stock. Aluminumis selected for cost reasons, with a primary cost savings in thataluminum is more quickly machined than steel, and a secondary costsavings in that the aluminum blocks themselves are less expensive thansteel. However, aluminum is not as strong as steel, and excessively thinstructures of aluminum will not withstand the forces imparted duringinjection molding. Accordingly, the program looks at the mold todetermine whether any portions of the mold are too thin. The cam 10 hasone thin recess, the notch 20, which if sufficiently thin and deep failsthis criterion. That is, as the cam 10 was designed by the customer, themold for the cam 10 cannot be formed of aluminum and withstand theforces of injection molding. Computer programmers will recognize that,once the acceptability criteria 44 are defined to include adetermination of whether the mold can be formed of aluminum, there aremany equivalent programming methods to apply this acceptabilitycriterion to the customer's CAD file 32.

One of the preferred inputs to the customer data input module 30 fromthe customer 34 is the type of plastic material which is selected forthe part 10. For instance, the customer data input module 30 may permitthe customer to select from any of the following standard plastics: ABS(natural), ABS (white), ABS (black), ABS (gray—plateable), Acetyl/Delrin(natural), Acetyl/Delrin (black), Nylon (natural), Nylon (black), 13%glass filled Nylon (black), 33% glass filled Nylon (black), 33% glassfilled Nylon (natural), 30% glass filled PET/Rynite (black),Polypropylene (natural), Polypropylene (black), Polycarbonate (clear),Polycarbonate (black), Ultem 1000 (black), Ultem 2200 (20% glass filled)(black), Ultem 2300 (30% glass filled) (black). Different plastics havedifferent viscosity curves at molding temperatures, differentsolidification rates, and different shrinkage rates. In the preferredembodiment, the program further reviews a fourth acceptability criterion46, of whether the mold geometry can be adequately injection molded withthe plastic material selected by the customer. This acceptabilitycriterion 46 involves an assessment of whether the mold contains areasthat will not shrink uniformly for the selected plastic material, andwhether gating can be readily machined into the mold, to result in anacceptable flow path for the plastic which will be met at an attainablemold temperature and pressure so the shot adequately and uniformly fillsthe cavity.

Additional acceptability criteria could be included, such as related tothe size of the part. For instance, the part may need to fit within amaximum projected area, as viewed through the straight-pull axis, of 50sq. in. (400 sq. cm). Similarly, the part may need to be smaller than amaximum part volume, such as a maximum volume of 18 cu. in. (200 cc).

If the customer's CAD file 32 fails one or more acceptability criteria40, 42, 44, 46, this failure is communicated to the customer. Ifdesired, the failure to meet any acceptability criteria 40, 42, 44, 46,may be communicated through a telephone call. However, preferably theprogram automatically generates a computer message which is transmittedto the customer, such as an e-mail. The preferred acceptability failuremessage indicates the nature of the failure. In the most preferredembodiment, the program includes a proposed modification CAD filecommunication module 56.

The proposed modification CAD file communication module 56 involvesseveral different steps. First, information is stored about each way inwhich the part 10 fails an acceptability criterion 40, 42, 44, 46. Forinstance, not only will information be stored that the cam 10 failsbecause the rib 22 is too thin and long and because the notch 20 is toodeep and thin, but information is also stored about the closest rib andnotch which would pass the acceptability criteria 42, 44. That is, bymaking the rib 22 slightly thicker, the rib 22 can be formed in the moldwith standard CNC endmills. By making notch 20 slightly thicker, thealuminum mold will withstand the forces of injection molding. Theproposed modification CAD communication module 56 then generates amodified CAD file 58, which distinguishes between the portions of thepart geometry which pass all acceptability criteria 40, 42, 44, 46 andthe portions of the part geometry which fail at least one acceptabilitycriteria 40, 42, 44, 46.

A drawing from the proposed modification CAD file 58 is shown as FIG. 6.The proposed modification CAD file 58 highlights the closestapproximations 60, 62, relative to remaining unaltered portions of thecam design part surface profile 10 which pass all acceptability criteria40, 42, 44, 46. Highlighting may be done through different line formats,different colors, etc. For instance, using one of predefined colorcoding schemes, colors are assigned to representative areas to show theidentified association of the machinable points and to indicate the lackof appropriate tool. The part geometry supplemented by the color data ispreferably placed in a file 58 using one of the standard graphicalformats suitable for rendering interactively manipulatedthree-dimensional views of the part 10. The file 58 together with thelegend explaining the color coding scheme used can be sent or otherwisemade available to the customer for interactive viewing, possibly withadditional comments. For instance, the file 58 might identify one ormore zero-drafted deep ribs. Comments included with the file 58 mayrequest that the customer redesign the part to introduce at least 0.5degree draft on deep ribs, or may say that the quote price can belowered if the rib's walls are drafted. The proposed modification CADcommunication module 56 then automatically transmits the proposedmodification CAD file 58 to the customer, so the customer can view thechanges required for inexpensive manufacture of the mold.

Skilled moldmakers will recognize that there are seldom mold designsthat can't be done, only mold designs that can't be done without addingsignificant complexity. For instance, a mold for the cam 10 asoriginally designed by the customer could be formed, but it would beformed of steel rather than aluminum and the rib portion 22 of the moldwould be burned by EMD. The present invention is configured based uponthe capabilities of the moldmaking shop. If the moldmaking shop canhandle CNC machined aluminum molds as well as EMD steel molds, then theprogram may assess acceptability criteria for both types of processes.If the customer's CAD file 32 fails at least one acceptability criteriafor the less expensive method of mold manufacture, then a first proposedmodification CAD file 58 maybe generated and transmitted to thecustomer. If the customer's CAD file 32 passes all acceptabilitycriteria for the more expensive method of mold manufacture, thisinformation may be transmitted to the customer as well.

The present invention thus provides a computerized method for fastidentification of the mold manufacturability issues. In ways that havenever been before contemplated in the moldmaking art, and in particularwithout requiring a face-to-face meeting between a customer and anexperienced moldmaker, mold manufacturability issues are automaticallyidentified and communicated to the customer. The three-dimensionalgraphical representation 58 of mold manufacturability issues is veryconvenient and considerably simplifies communication of such issues tothe customers. The geometry analyzer module 38 in tandem with theproposed modification CAD communication module 56 are valuable tools forthe design engineer. These modules 38, 56 can be used during thedevelopment process to guide the design toward a part 10 that can bemanufactured quickly and economically, whether or not it is quoted andmanufactured in accordance with the rest of the preferred system.

The next part of the preferred system is the quoting module 64. Ifdesired, quoting may be performed the prior art way, by having anexperienced moldmaker review drawings of the customer's part 10 andmeticulously consider what may be involved in making the mold. Morepreferably however, the quoting module 64 automatically generates aquotation 66 for the mold, and transmits the automatically-generatedquotation 66 to the customer 34.

To automatically generate a quotation 66, the program must assess one ormore cost parameters which are indicative of the real costs which willbe incurred to form the mold. The most basic cost parameters preferablyconsidered involve the machining actions which will be used to form themold. That is, the preferred quotation 66 varies based upon computeranalysis by the quoting module 64 of at least one indicator of moldmanufacture time. Automatic determination of machining actions and/orother material removal steps in the tool selection and tool pathcomputation module 68 is further detailed below. If machining actionsare automatically determined, then the quoting module 64 automaticallyassesses the determined machining actions to arrive at a quotation 66.

As one example, a primary indicator of overall mold manufacture time ishow long it takes to CNC machine the mold. A primary indicator of howlong it takes to CNC machine the mold is the number of steps in theseries of CNC machining instructions. Thus, the automatic quotation 66may be based in part or in full on the number of steps in the series ofCNC machining instructions.

As a further, more accurate iteration, how long it takes to CNC machinethe mold further depends upon which tools are used and what the materialremoval rate of each tool 50 is. Thus, the quoting module 64 storesinformation about a rate of material removal associated with each of thedifferent material removal steps. The preferred quoting module 64automatically identifies an estimated duration of material removalrequired for each discrete portion of the part surface profile. Theautomatic quotation 66 may be based in part or in full on a total ofestimated durations of material removal.

If desired, the Customer Data Input module 30 may permit the customer toselect a special surface finish, such as a polished finish, matte(similar to EDM), or special etched textures. If so, the automaticquotation may further vary based upon the difficulty in applying theselected special surface finish to the mold.

In general, the time required during material removal is only a portionof the time required for CNC machining. Additional time is required tochange from one tool to another. For instance, standard CNC machines mayinclude spots for 10 to 40 tools. Changing among these 10 to 40 toolstakes additional time. Further, a portion of the cost of CNC machiningis based upon the expense and wear rate of the tool 50. Some tools aremore expensive than others, and some tools need to be replaced morefrequently than others. Even more time and cost may be incurred if aspecial, custom or delicate tool is required for some material removalsteps. As a separate, more accurate enhancement, the quoting module 64may consider the number and type of tools used in the selected materialremoval steps.

A separate iteration which improves the accuracy of the quotation 66involves having the quoting module 64 consider the parting line andcorresponding shutoff surfaces of the mold. In general, simple moldswhich can be formed with an x-y planar parting line and shutoff surfacesare relatively inexpensive. A major portion of the expense of some moldsmay involve the time required to machine the parting line andcorresponding shutoff surfaces which are not x-y planar. Separate frombasing the quotation 66 on the number of CNC steps or on the estimateddurations of material removal, the automatic quoting module 64 mayconsider the complexity in forming the parting line and correspondingshutoff surfaces. Alternatively, the quoting module 64 may ignore thecomplexity of building shut-off surfaces that are necessary in thefull-blown mold design, particularly if the design of the shutoffsurfaces is not automated.

If the determined parting line is complex, it may be beneficial toinform the customer of the complexity in the parting line, either aspart of the manufacturability criterion 40 or as part of the quotingmodule 64. Thus the customer may be allowed to have input in selectionof a more simplified parting line, or the system may specificallysuggest to the customer that the parting line or particular features inthe part 10 which contribute to parting line complexity be moved.

Yet another separate indicator of mold manufacture time depends on thesize of the part 10. Larger molds often take more time. Larger moldscertainly require a greater expense in the cost of the raw mold blocks.The preferred quoting module 64 further accounts for the mold block arearequired for the part 10.

A further separate indicator of mold manufacture time involves ribbingand tightly radiused corners, as discussed previously with regard toacceptability criteria 40, 42, 44, 46 in the geometry analyzer module38. Deep grooves in the mold and sharper corners take more time tomachine. The preferred quoting module 64 further automatically assessesand accounts for the amount, depth and steepness of ribbing required forthe part 10.

A further separate indicator of mold manufacture time involvesevaluation of draft angle, as discussed previously with regard toacceptability criteria 40 in the geometry analyzer module 38. Evaluationof draft angle can be enhanced by including the minimal draft angle intothe mathematical expression for the price quotation. Steeper draftangles typically take more time and are more costly to machine. Further,parts with steeper draft angles are more difficult to eject from themold. The preferred quoting module 64 further automatically assesses andaccounts for the steepness of the draft angles required for the part 10,both as an indicator of mold manufacture time and as a potentialdifficulty in use of the mold during injection runs. With the preferredmold manufacturability acceptability criteria 40 requiring a draft angleof at least 0.5°, the preferred quoting module 64 includes additionalcosts (which vary based upon the draft angle) for draft angles in therange of 0.5 to 2.0°. If all sides are provided with draft angles of atleast 2.0°, then no additional cost allowance due to a steep draft angleis included by the preferred quoting module 64.

A further separate indicator of mold manufacturing difficulty and timedepends upon whether and which features cannot be standardly CNCmachined, but rather require EDM. The existence of any required EDMmaterial removal will increase the cost of the mold. Each feature whichrequires EDM will increase cost, and more so if the EDM feature is deepenough to require, because of electrode wear, multiple EDM electrodes.The preferred quoting module 64 identifies any different discreteportions of the part surface profile which are associated with differentelectrodes for EDM, and the automatically generated quotation 66 variesbased upon the estimated number of electrodes required.

Many customers have no injection mold experience or equipment, orotherwise are not interested in taking actual possession of the mold.While the cost to manufacture the mold may be the primary cost of thepart, customers often want parts, not molds. Accordingly, the preferredquoting module 64 quotes piece prices. Different piece price quotations66 may be given, for instance, for 10, 100, 1000, or 10000 parts. Inaddition to the cost of the mold, the primary cost considerations forpiece price quotations 66 depend upon what type of plastics material isused, and how much of it. The preferred quoting module 64 automaticallyprovides piece price quotations, which involve the cost of the mold andfurther vary based upon the volume of the part and the plastic materialselected by the customer for injection molding.

The quoting module 64 communicates the quotation 66 to the customer,preferably through the internet 36 such as through the website (ifreal-time quotation is attained) or through a responsive e-mail to thecustomer's computer 34. The customer may then accept the quotation 66through the same medium.

FIG. 10 depicts a screen shot 100 of a preferred customer interface forquoting module 64. The preferred quoting module 64 processes twodifferent types of information to arrive at a quotation. First, thesurface profile of the part 10 (which could have any of a virtuallyinfinite number of shapes) is assessed, to consider certaincost-affecting parameters determined by the part surface profile. Thesecond type of information is quite different from the infinitevariability of the shape information, and involves providing thecustomer with at least one menu of customer-selectable values for acost-affecting parameter unassociated with part surface profile.

For instance, a first preferred cost-affecting parameter unassociatedwith part surface profile is selected from a menu 102 of differingnumber of possible cavities. In order to provide the customer with amenu 102 of possible cavity numbers, the size and layout of the moldcavity 84 must first be assessed relative to the size of mold blocksavailable. For instance, a size comparison and mold layout analysis forone part 10 may result in a possibility of up to eight identicalcavities being formed within a single mold block. The customer is thenprovided with a drop-down menu 102 of the number of possible cavities,for the customer to select between menu values of “1 cavity”, “2cavities”, “4 cavities”, and “8 cavities”.

For a different part (not shown), the size comparison and mold layoutanalysis may result in a possibility over only four identical cavitiesbeing formed within a single mold block, in which case the drop-downmenu 102 of the number of possible cavities for that part would onlyprovide selectable values of “1 cavity”, “2 cavities” and “4 cavities”.

The number of cavities selected by the customer is then evaluated in thequoting module 64 as a cost parameter both for mold cost and for pieceprice cost, with mold cost increasing due to the additional time andcost required to machine more cavities, but with piece price costdecreasing because multiple parts can be run with each shot. Thepreferred quoting module computes a quotation on the basis of amathematical expression which describes several components of theprice—such as the cost of mold block, milling time, polishing time,setup-time in the press, etc. Some of these components may beindependent of the number of cavities (e.g., setup time), some aredirectly proportional to the number of cavities (such as polishingtime), some exhibit more complex dependance (for example, the cost ofmold block for small parts does not depend on the number of cavitiesprovided that several cavities fit in the same block—but increases ifbigger mold block is needed). The quoting module 64 re-computes thequotation each time when the customer changes the available preferences.

A second preferred cost-affecting parameter unassociated with partsurface profile which is menu selectable is surface finishes. Thecustomer is provided with a drop-down menu 104 of offered surfacefinishes. For example, the customer may be provided with a drop-downmenu 104 which allows the customer to select between values of “T-0(finish to Protomold discretion. Tool marks may be visible)”, “SPI-C1(600 Stone)”, “SPI-B1 (400 Paper)”, “T-1 (Medium bead blastfinish—similar to a medium EDM finish)”, “T-2 (Coarse bead blast finishsimilar to a coarse EDM finish)” and “SPI-A2 (High Polish)”. In thepreferred quoting module 64, the customer may select any of thesedifferent menu-provided surface finishes from a different drop-down menu104, 106 for each side of the mold.

In an alternative embodiment (not shown), the customer may be permittedto select different surface finishes between different faces even on thesame side of the mold. To avoid naming confusion over the differentfaces, the alternative quoting module provides a graphicalrepresentation of each side of the part with different faces marked withindicia, such as shaded in different colors. The quoting module thenprovides a drop-down menu for each colored shading on the graphicalrepresentation (i.e., “surface finish for blue face” menu, “surfacefinish for red face” menu, etc.) so the customer can select the surfacefinish applied to each colored face of the depicted cavity 84.

Once the customer selects the drop-down menu value for the surfacefinish, the quoting module 64 assesses the cost of applying the selectedsurface finish for the cavity 84, computed based upon the time,materials and tools required to apply the selected surface finish,preferably also as a function of the surface area for the appliedfinish.

A third preferred cost-affecting parameter unassociated with partsurface profile which is menu selectable is material of the part. Thecustomer is provided with a drop-down menu 108 of offered materials. Thematerial or resin used for the part 10 is an integral consideration inthe design process, affecting many material properties of the part 10such as strength, flexibility, hardness, corrosion resistance,flammability, etc. Further, cost of each plastic material or resin issubject to change due to market conditions. Accordingly, the preferredmaterial menu 108 provides numerous alternatives. For example, thecustomer may be provided with a drop-down menu 108 which allows thecustomer to select between the following seventy values: “Customersupplied”, “ABS, Natural (LUSTRAN 433-1050)”, “ABS, Black (CYCOLACT-4500)”, “ABS, Black (LUSTRAN 433-4000)”, “ABS, White (LUSTRAN248-2005)”, “ABS, Black (POLYLAC PA-765)”, “ABS Platable, Light Grey(LUSTRAN PG298)”, “ABS Platable, Gray (CYCOLAC MG37EP)”, “ABS/PC, Black(BAYBLEND FR 110-1510)”, “ABS, White (LUSTRAN 248-2005)”, “ABS/PC, LightGray (BAYBLEND T85 2095)”, “ABS/PC, Black (CYCOLOY C2950-701)”, “ABS/PC,Natural (BAYBLEND T 45-1000)”, “ABS/PC, Black (BAYBLEND T 85-1510)”,“ABS/PC, Black (BAYBLEND T85 2D95)”, “Acetal Copolymer, Black (CELCONM90)”, “Acetal Homopolymer, Black (DELRIN 500 P BK602)”, “AcetalHomopolymer, Natural (DELRIN 500P NC010)”, “Acetal Homopolymer, 20% GF,Black (DELRIN 577-BK000)”, “Acetal Homopolymer, Black (DELRIN 500 CLBK601)”, “HDPE, Natural (HiD 9006)”, “LDPE, Natural (DOW LDPE 722)”,“Nylon 46, Natural (STANYL TW341)”, “Nylon 6, Natural (ZYTEL 7331FNC010)”, “Nylon 6, Black (ZYTEL 7331F dyed)”, “Nylon 6, Black (RTP 200AFR)”, “Nylon 66, Black (ZYTEL 101L BKB009)”, “Nylon 66, 13% GF, Black(ZYTEL 70G13 HSIL)”, “Nylon 66, 14% GF, Black (ZYTEL 8018 HS)”, “Nylon66, 43% GF, Black (ZYTEL 74G43W BK196)”, “Nylon 66 33% GF, Natural(ZYTEL 70G33HSIL)”, “Nylon 66, 33% GF, Black (ZYTEL 70G33 HSIL BK031)”,“Nylon 66, Natural (ZYTEL 103 HSL)”, “Nylon 66, Natural (RTP 202 FR)”,“PBT 30% GF, Black (VALOX 420 SEO)”, “PBT 15% GF, Black (CRASTIN SK 652FR)”, “PBT, Black (VALOX 357-1066)”, “PC, Opaque/White (MAKROLON2558-3336)”, “PC, Black (LEXAN 940)”, “PC, Clear (MAKROLON 2405-1112)”,“PC, Clear (MAKROLON 2458-1112)”, “PC, Black (MAKROLON 2405-1510)”, “PC,10% Glass, Black (MAKROLON 9415-1510)”, “PC 20% GF, Natural (MAKROLON8325-1000)”, “PC 20% Glass, Black (MAKROLON 8325-1510)”, “PC, clear(MAKROLON 6455-1045)”, “PC, Infrared (LEXAN 121-S80362)”, “PEI, Black(ULTEM 1000-7101)”, “PEI, 20% GF, Black (ULTEM 2200-7301)”, “PEI 30% GF,Black (ULTEM 2300-7301)”, “PEI, 40% GF, Black (ULTEM 2400-7301)”, “PET30% Glass, Black (RYNITE 530-BK503)”, “PET 45% Glass Mineral FlameRetardant, Black (RYNITE FR 945 BK507)”, “PET 35% Glass Mica Low Warp,Black (RYNITE 935 BK505)”, “PETG, Clear (EASTAR 6763)”, “PMMA Clear(PLEXIGLAS V052-100)”, “PP 20% Talc Filled, Natural (MAXXAM NR218.G001-1000)”, “PP, Black (MAXXAM FR 301)”, “PP Copolymer, Natural(PROFAX 7531)”, “PP Copolymer, Natural (PROFAX SR 857M)”, “PPHomopolymer, Natural (PROFAX 6323)”, “PP Homopolymer, Natural (PROFAX6523)”, “PS (GPPS), Clear (STYRON 666 Dwl)”, “PS (HIPS), Black (RC3502B)”, “PS (HIPS), Natural (STYRON 498)”, “PUR, Natural (ISOPLAST202EZ)”, “TPE, Natural (SANTOPRENE 211-45)”, “TPE, Black (SANTOPRENE101-73)”, “TPU—Polyester, Black (TEXIN 285-1500)” and “TPU—Polyether,Natural(TEXIN 985-1000)”.

Once the customer selects the drop-down menu value for the material, thequoting module 64 assesses the cost of using the selected material. Theprimary input into the quotation module 64 based upon the selectedmaterial is the current raw material cost multiplied by the computedvolume of the part plus sprews and runners. However, other costsconsiderations of the selected material may also be taken into account,such as ease of working with the material, wear on the mold 86 caused bythe material, and shrink factor of the material. If the customer selects“customer supplied”, then the quotation module 64 minimizes the cost ofthe raw material itself, but maximizes the cost of working with thematerial to account for potential difficulties.

A fourth preferred cost-affecting parameter unassociated with partsurface profile which is menu selectable is the estimated delivery date.For instance, the customer may be provided with a menu 110 permittingselection of a delivery date of “within 5 business days” or “10-15business days”. Alternatively, additional or more specific levels ofdelivery date pricing may be provided. The preferred quotation module 64thus includes a premium charged for rushed processing.

A fifth preferred cost-affecting parameter unassociated with partsurface profile which is menu selectable is the number of parts or lotsize for piece price quotation. For instance, the customer may beprovided with a menu permitting selection of a piece price quotation inlots sizes of “100”, “500”, “1,000”, “2,000”, “5,000”, “10,000”,“20,000”, “100,000” or “200,000” parts. This piece price quotation maythen be provided to the customer separately from the tooling charge.Alternatively, the preferred quotation module 64 quotes prices 112 forall these different lot sizes, so the customer can readily see how thelot size affects the piece price.

In the preferred system, the quoting module 64 operates in conjunctionwith the geometry analyzer module 38 to provide graphical feedback tothe customer. Preferably, this feedback occurs in real time to allow thecustomer to redesign physical features of the part 10 (i.e., change theunderlying CAD file 32 for the part 10) while obtaining real-timequotation information of how the redesign affects the quotation.

The quoting module 64 is another important tool which can be used bydesign engineers separately from other facets of the preferred system,such as to compare different design alternatives. Since it is fast andeasy, instant online quoting is a powerful tool for budgeting andcomparing design alternatives during the development process. Designengineers may use online quoting several times in the design of a singlepart and online quoting will become a very important part of theirdesign process.

The next part of the preferred embodiment involves the tool selectionand tool path computation module 68. The tool selection and tool pathcomputation module 68 may be activated upon receipt of an acceptedquotation 66, but more preferably operates in conjunction with thequoting module 64 as discussed earlier. The task of the tool selectionand tool path computation module 68 is to determine what tools to useand what tool paths should be used with those tools to efficientlymanufacture the mold for the part specified by the CAD file 32 of thecustomer.

As an initial step, the predicted shrinkage 70 of the plastic materialupon solidification is applied to the CAD file 32. Based upon theplastic material that the customer indicates will be used to thecustomer data input module 30, the dimensions are increased inaccordance with known shrinkage factors. Subsequent calculations in thetool selection and tool path computation module 68 are based upon thesize of the cavity (before shrink, as determine by a shrinkage factor70) rather than size of the part 10 (after shrink).

As a second initial step, standard mold block sizes are assessed todetermine mold block layout 72. Mold layout 72 is the process ofassigning and locating one or more core/cavities onto a standardizedmold base. For small, simple parts, two or more identical cavities maybe machined into a standard sized mold block. A family mold containsmore than one unique part, and is often used to reduce tooling cost fora group of parts that are used together. A multi-cavity mold usuallyrefers to a mold with multiple copies of the same part. This approach iscommonly used to reduce per part costs when expected production volumewill be significant. Either or both approaches may be utilized using thepresent invention. Selecting one of several standard mold base sizesdetermines the size of the raw block of aluminum from which the moldwill be formed. If the automatic quoting module 64 is used, informationabout which standard size of mold block is to be used and the number ofcavities in the mold as selected in mold layout 72 is fed back to theautomatic quoting module 64.

Before any selection of tools and computations of tool paths can beperformed, the orientation of the part relative to the mold must bedetermined. While this could be performed manually by an experiencedmoldmaker, the preferred automated method was described earlier withreference to automatic “straight pull” manufacturability identification40 as one of the acceptability criteria.

Once the orientation of the part relative to the mold is determined, theparting line and corresponding shutoff surfaces are selected 74. Theparting line and corresponding shutoff surfaces should be oriented withrespect to the part to permit straight pull of the first half and thesecond half in a straight-pull z-direction during molding of the part.Again, selection of the parting line and corresponding shutoff surfacescould be performed manually by an experienced moldmaker. In thepreferred embodiment, the parting line and corresponding shutoffsurfaces are automatically oriented 74 with respect to the part 10 asfollows.

The CAD file 32 is assessed to automatically determine all edge surfaceswhich extend parallel to the straight-pull z-direction. For a moment,the parallel edge surfaces are excluded from the determination, asdetermining the parting line for the other portions of the part 10 isrelatively easy. If an edge surface does not extend parallel to thestraight-pull z-direction, then the parting line is at the height of thegreatest areal extent of the part. Thus, the parting line/shutoffsurface portion 74 of the tool selection and tool path computationmodule 68 automatically defines parting line segments which extend alongthe uniquely (non z-direction) extending greatest periphery of the part10. If an edge surface does not extend parallel to the straight-pullz-direction, then the parting line is at the height of the greatestareal extent of the part. The cam 10 has no uniquely (non z-direction)extending periphery of the part, as the part outline flange 12, thecircular opening 14, the two rotation pins 16, the non-circular opening18, the notch 20, the 60° corner hole 24, the 30° corner hole 26, andthe partial web 28 all provide edge surfaces which extend in thez-direction.

The unique parting line segments (if any) must now be connected withinthe edge surfaces which extend parallel to the straight-pullz-direction. Preferably, the parting line selection routine 74 uses theCNC machining criterion 42 and verifies potential z-direction heights ofthe parting line segments within the parallel edge surfaces, to assurethat the selection of the parting line comports with the desiredmachinability of the mold. For instance, if tool 50 is being used tomachine the bottom mold block at a parallel edge surface of the partoutline flange 12, and if tool 50 has a cutting depth 52 of two inches,then the parting line segment must be within the bottom two inches ofthe parallel edge surface of the part outline flange 12.

Once any unique parting line segments are defined and the CNC machiningcriterion 42 is verified, the parting line selection routine 74 can useany of several optimization routines. For the shortest parting line, theparting line segments within the parallel edge surfaces simply connectthe unique and CNC defined parting line segments. To the extentpossible, the parting line should be designed to be no steeper than 5-10degrees. Preferably, a smoothing routine is used to define curvedparting line segments within the parallel edge surfaces. In thepreferred embodiment, a second derivative of the parting line (i.e., theinstantaneous change in slope of the parting line) is minimized inconjunction with minimizing the length of the parting line.

Shutoff surfaces within the mold are automatically determined in muchthe same way. The shutoff surfaces are those surfaces where the moldhalves will contact each other when the mold is closed. First, theshutoff surfaces by definition include the parting line. If the partingline is planar, with no holes inside the part, the shutoff surface isdefined to be coplanar with the parting line. In the case of the cam 10,the circular opening 14 and the non-circular opening 18 also representareas of contact between the shutoff surfaces for the two parts of themold. The parting line around the part outline flange 12, the partingline around the circular opening 14 and the parting line around thenon-circular opening 18 can each be planar. The shutoff surface at thecircular opening 14 can be planar, as can the shutoff surface at thenon-circular opening 18. Defining the shutoff surfaces can be verycomplex in the case of a part with a highly articulated parting line andcomplex internal telescoping shutoffs. Beyond considering the partingline, the preferred embodiment 74 optimizes the selection of the shutoffsurfaces. To the extent possible, the shut-off surfaces should bedesigned to be no steeper than 5-10 degrees. While a straight-lineroutine could be used, the preferred embodiment uses a three-dimensionalsmoothing routine.

The preferred smoothing routines create a parting line shutoff surfacewhich is mathematically complex, and virtually impossible to handmachine. However, the complex surface is mathematically defined, andtranslated into CNC machining instructions. In the CNC machininginstructions, the mathematical complexity of the curve is notparticularly important. What is important in the CNC machininginstructions is that the shut off surfaces are as smooth as possible,and thus can be formed with the largest tool(s) possible and at thefastest material removal rates. Automatic selection 74 of the partingline and corresponding shutoff surfaces thus provides for: (a) a fastassessment of acceptability criterion 42; (b) a fast quotation 66; (c) afast generation of CNC machining instructions 76; and (d) a fast CNCmachining operation 78 to fabricate the mold.

After the parting line and the shutoff surfaces 74 are determined, thepreferred method uses the geometry analyzer module 38 to automaticallydetermine the tools and material removal steps required to form thecavity or cavities. The cavity is split in two parts, one for the topmold block and the other for the bottom mold block. In contrast to theshutoff surfaces, which are defined identically but opposite for the twomold blocks, the cavity obviously may have different top and bottomshapes. For each of the two cavity surfaces, the geometry analyzermodule 38 generates a cloud of points dense enough to represent the partgeometry with acceptable tolerance. For each point in the cloud, thegeometry analyzer module 38 traverses the set of machining toolsavailable. That is, a collection of information of standard toolgeometries and surface profiles machinable by each of the standard toolgeometries is created and stored in the program 38. Because we havealready defined the system constraints to include straight-pullmanufacturability 40, the preferred collection of information is onlyconsidered in the CNC machine with the mold block oriented relative tothe tool in the straight-pull z-direction. This stored information isconsidered by the geometry analyzer module 38 to determine which toolsare available to machine a small vicinity of each point without gougingmore distant parts of the partial surface either with the tip or shankof the tool 50 or with the collet 54 holding the tool 50. The toolinformation is traversed starting from the most efficient (fastestmaterial removal, lowest cost) tool and going in the direction ofdecreasing tool efficiency. The traversal is stopped when several toolsthat can machine the current point without gouging are found. Theassociation between the points and the identified most effectivenon-gouging tools is stored in the memory.

If, for the current point, a non-gouging tool could not be found at all,this fact is also stored in memory. The failure to find a non-gougingtool can then be used as the basis for the proposed modification CADfile communication module 56 discussed earlier.

For the collection of points which can be machined, the geometryanalyzer module 38 uses a tool selection optimization routine 80 whichselects the most efficient tool. In general, the collection ofmachinable points should be machined with as few tool changes aspossible, but still at the highest rate of material removal. The toolselection and tool path computation module 68 automatically identifiesand locates discrete machinable portions of the part surface profilewhich can be machined with a single tool 50, and records the mostefficient tool path for that tool 50.

As noted earlier, the preferred tools used in the CNC machining processmost commonly include standard-sized endmills. For instance, much of thesurface profile for the cavity for the cam 10 can be efficientlymachined with the ¼ endmill 50. FIG. 7 is a “screen-shot” representing aportion of an optimized tool path 82 generated so as much of the cavity84 as possible for the cam 10 can be machined by CNC machining with the¼ endmill 50.

The preferred tool selection and tool path computation module 68determines the other portions of the mold 86 as well. In particular, thepreferred tool selection and tool path computation module 68automatically identifies 88 sizes and locations of ejector pins 90, asshown in FIG. 8. Ejector pins 90 are used to push the part 10 out of themold 86 after it has been formed. In general, ejector pin selection 88considers the profile of the mold 86 to determine the deepest locationswhich provide significant surface area extending perpendicular to thestraight-pull z-direction. The ejector pin selection routine 88 centersejector pin locations on these flat surfaces, and sizes the ejector pins90 by selecting the largest standard size that will fit within each flatsurface.

The preferred tool selection and tool path computation module 68 alsoautomatically identifies 92 sizes and locations of runners 93 and gates94, as shown in FIG. 9. A gate 94 is the place on the mold 86 where theplastic is injected into the mold cavity 84 as a part is being produced.A runner 93 is the path on the mold 86 where the molten plastic travelsto get from the molding machine to the gate(s) 94 and into the partcavity 84. The sizes of runners 93 and gates 94 are selected 92 fromknowledge of standard cutting tool sizes, based upon the plasticmaterial selected by the customer, the volume of the part, and the knownflow constraints of that plastic material. The locations of the gates 94are generally selected 92 to connect to the part 10 on a surface whichextends parallel to the z-direction, and to minimize seam lines in thepart 10 based upon flow geometry. The locations of the runners 93 aregenerally selected 92 to be as straight as possible from the spruelocation 96 to the gates 94.

Once the parting line and shutoff surfaces 98 have been defined (step74), the mold layout has been specified 72, the tools have been selected68, and the tool paths for the cavity 84 have been computed 80, thepreferred method includes a CNC instruction generation module 100 whichgenerates the detailed instructions 76 that will be used by the CNCmilling equipment to cut the mold 86 from a raw block of aluminum. TheCNC instruction generation module 100 generates a series of CNCmachining instructions 76 corresponding to machining the mold 86 withthe selected tools and computed machining actions. For instance, the CNCinstruction generation module 100 may generate a “g-code” programcontaining a set of instructions 76 for CNC milling machines. Ifdesired, the shape of the cavity 84 as machined in the mold block can bevisualized with one of the g-code viewers developed for up-front visualverification of machining under the control of g-code programs, and theshape of the cavity 84 can be visually compared with drawings of thepart 10. CNC machining instructions 76 are generated to machine ejectorpin locations 90, sprues 96, runners 93, gates 94 etc. into the moldblocks.

The final step in the preferred process is machining 78 the mold 86. Theshutoff surfaces 98 are machined into the mold blocks with the selectedtools and computed machining actions and via the computer generatedseries of CNC machining instructions 76. The cavity 84 is likewisemachined into the first and second halves of the mold 86. Locations forejector pins 90 are machined into the first and second halves of themold 86 via the computer generated series of CNC machining instructions76, as are runners 93 and gates 94.

If the quotation 66 involve a piece price quotation, the number ofpieces ordered by the customer are run in an injection mold press. Thepieces are shipped back to the customer. The customer is billed inaccordance with the quotation 66.

The present invention allows mass production techniques to be used inthe moldmaking process, even though every mold is custom designed,custom machined and different.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. As one example, while the present inventionhas been described with relation to various patentable features beingpreformed in separately named modules, computer programmers willrecognize many equivalent options exist for naming of the modules andorganization of the programming features. As another example, while thepresent invention as described is constrained to require straight-pull,two-piece molds, enhancements may be made to support side actions in themold. Permitting side action molds will overcome the current requirementthat parts be producible in simple straight-pull molds. Side actionmolds allow molding parts with undercut faces—faces that cannot beplaced entirely in one subset because they have areas that needmachining from opposite directions. Permitting side action molds willthus increase the percentage of parts that are eligible for theautomated process.

What is claimed is:
 1. A method of automated, custom quotation formanufacture of a mold and/or manufacture of a molded part, the molddefining a cavity corresponding in shape to the part to be molded, themethod comprising: receiving a CAD file for the part to be molded, theCAD file defining a part surface profile; assessing cost-affectingparameters of mold manufacture and/or part manufacture determined by thepart surface profile; providing the customer with at least one menu ofcustomer-selectable values for a cost-affecting parameter of moldmanufacture and/or part manufacture unassociated with part surfaceprofile; allowing the customer to select one of the providedcustomer-selectable values; automatically generating a quotation formold manufacture and/or part manufacture based in part upon thecost-affecting parameters determined by part surface profile and basedin part upon the customer-selected value; and automatically transmittingthe automatically generated quotation to the customer.
 2. The method ofclaim 1, wherein the CAD file is received directly from the customer. 3.The method of claim 1, wherein the at least one menu ofcustomer-selectable values for a cost-affecting parameter of moldmanufacture and/or part manufacture unassociated with part surfaceprofile comprises a menu of possible number of cavities in the mold,such that the automatically generated quotation varies based upon howmany cavities the customer selects for the part.
 4. The method of claim1, wherein at least one menu of customer-selectable values for acost-affecting parameter of mold manufacture and/or part manufactureunassociated with part surface profile comprises a menu of availableinjection moldable plastics, such that the automatically generatedquotation varies based upon which plastic the customer selects for thepart.
 5. The method of claim 1, wherein at least one menu ofcustomer-selectable values for a cost-affecting parameter of moldmanufacture and/or part manufacture unassociated with part surfaceprofile comprises a menu of possible surface finishes, such that theautomatically generated quotation varies based upon which surface finishthe customer selects for the part.
 6. The method of claim 1, wherein atleast one menu of customer-selectable values for a cost-affectingparameter of mold manufacture and/or part manufacture unassociated withpart surface profile comprises a menu of number of parts in a productionrun, such that the automatically generated quotation non-linearly variesbased upon how many parts the customer selects to be run.
 7. The methodof claim 1, wherein the automatically generated quotation comprises aseries of piece price quotations covering different lot sizes, theseries of piece price quotations varying non-linearly based upon howmany parts the customer selects to be run.
 8. The method of claim 1,wherein at least one menu of customer-selectable values for acost-affecting parameter of mold manufacture and/or part manufactureunassociated with part surface profile comprises a menu of potentialdelivery times, such that the automatically generated quotationnon-linearly varies based upon lead time required by the customer. 9.The method of claim 1, further comprising: automatically determiningphysical geometry modification locations for the CAD file on the part tobe molded; creating a proposed modification CAD file which highlightsthe physical geometry modification locations relative to remainingunaltered portions of the part surface profile, wherein theautomatically generated quotation is based upon the proposedmodification CAD file; and transmitting a rendering of the proposedmodification CAD file to the customer together with the automaticallygenerated quotation.
 10. The method of claim 1, wherein the act ofassessing cost-affecting parameters determined by the part surfaceprofile comprises: computer generating a series of CNC machininginstructions corresponding to machining the mold to match the partsurface profile, wherein the automatically generated quotation is basedupon the computed CNC machining instructions.
 11. The method of claim 1,wherein the act of assessing cost-affecting parameters determined by thepart surface profile comprises: determining a parting line andcorresponding shutoff surfaces between separable portions of the mold,wherein the automatically generated quotation varies based uponcomplexity of the parting line and corresponding shutoff surfaces. 12.The method of claim 1, wherein the act of assessing cost-affectingparameters determined by the part surface profile comprises:automatically identifying an estimated duration of material removalrequired for each discrete portion of the part surface profile, andwherein the automatically generated quotation varies based upon a totalof estimated durations of material removal.
 13. The method of claim 1,wherein the act of assessing cost-affecting parameters determined by thepart surface profile comprises: automatically identifying the number andtype of tools to be used in selected material removal steps for themold, and wherein the automatically generated quotation varies basedupon the number and type of tools to be used in selected materialremoval steps for the mold.
 14. The method of claim 1, wherein the actof assessing cost-affecting parameters determined by the part surfaceprofile comprises automatically assessing mold block area required forthe part, and wherein the automatically generated quotation varies basedupon required mold block area.
 15. The method of claim 1, wherein theact of assessing cost-affecting parameters determined by the partsurface profile comprises automatically assessing amount, depth andsteepness of ribbing required for the part, and wherein theautomatically generated quotation varies based upon the required amount,depth and steepness of ribbing.
 16. The method of claim 1, wherein thecustomer is provided with at least one menu of customer-selectablevalues on an internet web page.
 17. A method of automated, customquotation for manufacture of a mold and/or manufacture of a molded part;the mold defining a cavity corresponding in shape to the part to bemolded, the method comprising: receiving a CAD file for the part to bemolded, the CAD file defining a part surface profile; automaticallydetermining physical geometry modification locations for the CAD file onthe part to be molded; creating a proposed modification CAD file whichhighlights the physical geometry modification locations relative toremaining unaltered portions of the part surface profile, automaticallygenerating a quotation for mold manufacture and/or part manufacturebased at least in part upon the cost-affecting parameters determined bypart surface profile as modified in the proposed modification CAD file;and transmitting a rendering of the proposed modification CAD file tothe customer together with the automatically generated quotation.
 18. Asystem for automated, custom quotation for manufacture of a mold and/ormanufacture of a molded part; the mold defining a cavity correspondingin shape to the part to be molded, the system comprising: an addressconfigured to receive a CAD file from a customer for the part to bemolded, the CAD file defining a part surface profile; and one or moreprocessors collectively programmed for: providing the customer with aninternet page supplying at least one menu of customer-selectable valuesfor a cost-affecting parameter of mold manufacture and/or partmanufacture unassociated with part surface profile; automaticallygenerating a quotation for mold manufacture and/or part manufacturebased in part upon the cost-affecting parameters determined by partsurface profile and based in part upon the customer-selected value; andautomatically transmitting the automatically generated quotation to thecustomer over the internet.
 19. A method of automated, custom quotationfor manufacture of a mold and/or manufacture of a molded part, the molddefining a cavity corresponding in shape to the part to be molded, themethod comprising: receiving a CAD file for the part to be molded, theCAD file defining a part surface profile; assessing cost-affectingparameters of mold manufacture and/or part manufacture determined by thepart surface profile; receiving additional information from the customerimpacting upon a cost-affecting parameter of mold manufacture and/orpart manufacture unassociated with part surface profile; automaticallygenerating a quotation for mold manufacture and/or part manufacturebased in part upon the cost-affecting parameters determined by partsurface profile and based in part upon the additional informationreceived; and automatically transmitting the automatically generatedquotation to the customer.
 20. A system for automated, custom quotationfor manufacture of a mold and/or manufacture of a molded part; the molddefining a cavity corresponding in shape to the part to be molded, thesystem comprising: an address configured to receive a CAD file from acustomer for the part to be molded, the CAD file defining a part surfaceprofile; and one or more processors collectively programmed for:assessing cost-affecting parameters of mold manufacture and/partmanufacture determined by the part surface profile; automaticallygenerating a quotation for mold manufacture and/or part manufacturebased in part upon the cost-affecting parameters determined by partsurface profile and based in part upon additional information receivedfrom the customer impacting upon a cost-affecting parameter of moldmanufacture and/or part manufacture unassociated with part surfaceprofile; and automatically transmitting the automatically generatedquotation to the customer over the internet.